The present invention generally relates to paper transport mechanism, and more particularly to a paper transport mechanism which is suited for use in an image forming apparatus such as a copying machine.
FIG. 1 shows a side view of a conceivable copying machine with a side panel thereof omitted for the sake of convenience. In FIG. 1, a plurality of cassettes 1 are provided in a plurality of stages at predetermined intervals along the vertical direction. Each cassette 1 stores paper 2 which is fed by pickup rollers 3. A transport mechanism 4 transports the paper 11 fed from the pickup rollers 3 to a recording part 5 which records an image on the paper 2. A fixing unit 6 fixes the image which is transferred onto the paper 2 in the recording part. The paper 2 from the fixing unit 6 is ejected onto a tray 7 which stacks the paper 2.
The transport mechanism 4 includes a first guide plate 8 for paper transport, second guide plates 9 for paper transport, and first through third rollers 11, 12 and 13. The second guide plates 9 have the same structure, and confront the first guide plate 8 with a gap formed therebetween. The first rollers 11 are provided on the first and second guide plates 8 and 9, respectively, and the second and third rollers 12 and 13 are respectively provided on each second guide plate 9. The first rollers 11 provided on the first guide plate 8 make pressing contact with the first rollers provided on the second guide plate 9. On the other hand, the second rollers 12 make pressing contact with the corresponding third rollers 13.
The two end parts of each second guide plate 9 are curved towards the cassettes 1. The surface at the end part of one second guide plate 9 confronts the surface of the end part of another second guide plate 9 which is located above or below the one second guide plate 9 with a gap formed therebetween.
If a paper jam occurs in the transport mechanism 4, the first guide plate 8 is opened as shown in FIG. 2 so as to open the transport path. The paper 2 causing the paper jam is the removed from the transport path.
However, the transport path which is formed between two adjacent second guide plates 9 is not opened even when the first guide plate 8 is opened. For this reason, it is difficult to remove a paper 2 jammed between two adjacent second guide plates 9. In some extreme cases, it is impossible to reach for and remove the paper 2 which is stuck between two adjacent second guide plates 9.
If the user cannot reach the paper 2 which is stuck between two adjacent second guide plates 9, the user manually rotates the second roller 12 or the third roller 13 so as to eject the paper 2. However, this manual operation is troublesome for the user to perform. In addition, this manual operation may cause an erroneous operation which may tear the paper 2 which is stuck between the two adjacent second guide plates 9. A torn piece of paper 2 may cause a failure of the copying machine which cannot be repaired by the user, and there are problems in that a service person must attend to the repair and that the copying machine will not be usable for a long time.
These problems of the copying machine also occur in other image forming apparatuses such as printers and facsimile machines which have a paper transport mechanism.